This invention relates to an electric powered rotary saw and more particularly to an electric powered rotary hacksaw for cutting tubing or the like.
Annular saws that rotate and which are driven by the friction of a roller acting on a saw blade are well known. For example, the U.S. patent of Santilli, No. Re 27,716 discloses an annular saw with a circular safety guard. As disclosed therein conical rollers rotate an annular saw blade about an axis. This saw blade includes a plurality of cutting teeth about the periphery of the blade. A portion of the saw blade is protected by a casing. As disclosed in the patent, the saw blade is provided with a circular guard which conceals nearly the entire saw blade""s tooth periphery and gradually exposes it only when the workpiece is fed to the saw.
Apparatus for damping vibrations of rotary cutting blades are also known. For example, the U.S. patent of Allison, U.S. Pat. No. 3,797,354 discloses such apparatus. As disclosed therein, the planar surface of a rotary cutting blade is frictionally contacted by a damping means comprising a plurality of coaxial independent rotatable discs each presenting a relatively narrow peripheral surface in contact with the planar surface and intersecting the axis of rotation of the cutting blade. The apparatus includes a frustoconical surface or a plurality of spaced coaxially frustoconical roller segments. Means are provided for adjusting the frictional contact between the damping means and the planar surface.
Notwithstanding the above, it is presently believed that there may be a commercial demand for an electric powered rotary hacksaw in accordance with the present invention. There may be a demand since the electric powered rotary hacksaw in accordance with the present invention is relatively light, can be produced in relatively small sizes with minimal complexity and may be designed and constructed for specific applications such as cutting copper tubing or the like. Further, it is presently believed that the rotary hacksaws of the present invention will reduce problems associated with vibration, are light in weight, durable and can be manufactured and sold at a competitive price. A preferred embodiment of the invention is particularly applicable for cutting copper tubes or plastic tubing commonly used in plumbing applications.
In essence, the present invention contemplates an electric powered rotary hacksaw comprising a housing and a longitudinally extending mounting member extending outwardly from the housing. The rotary hacksaw includes an annular and preferably a circular blade having a generally planar surface and a plurality of cutting teeth along a peripheral edge thereof. The cutting blade also includes a driving portion inwardly from the cutting teeth and preferably nearer to the cutting teeth than to the center of rotation. The cutting blade is disposed in a first plane and is rotatable about a first axis of rotation. An electric motor is disposed in the housing and includes a rotatable shaft which is rotatable about a second axis of rotation which is generally transverse of the first axis of rotation. An elastomeric preferably a relatively hard rubber frustoconical driver is disposed on a rotatable shaft for rotation by the electric motor. The elastomeric driver is brought into contact with the driving portion of the cutting blade to rotate the blade about the first axis and to displace the driving portion and cutting teeth of a blade out of the first plane.
The invention will now be described in connection with the accompanying drawings wherein like reference numerals have been used to define like parts.